Mobile communications device, controller, and method for controlling a mobile communications device

ABSTRACT

A mobile communications device. includes a communication unit for communicating with another device. The mobile communications device further has a communication unit for communicating with another device and at least one other component. A controller is connected to the communication unit and the component. The controller can control the component, during at least a part of time the communication unit is in a communicating mode, based on an operation of the communication unit.

FIELD OF THE INVENTION

This invention relates to a mobile communications device, to acontroller, to a method for controlling a mobile communication deviceand to a kit of parts.

BACKGROUND OF THE INVENTION

Mobile communication devices, such as mobile telephones provided with acamera are known. The mobile telephone has a camera which can capture animage of an object and a flash-light which can generate a light flash inorder illuminate the object when the camera generates the image. Themobile telephone further has a transceiver which can transmit andreceive radio signals. The transceiver is connected to a power source, a1000 mAh lithium-based chemical battery, which provides power to thetransceiver.

However, a disadvantage is that the light source and the transceiver cannot operate simultaneously. The transceiver includes a power amplifierwhich uses about 1 A of current during peak operation, whereas the lightsource typically draws a peak current of 1 A from the battery during theflash. In case the peak current from the power amplifier and the lightsource occurs simultaneously, the battery has to deliver a current ofseveral amperes during several milliseconds. This amount of current maycause a drop in the supply voltage due to the internal resistance of thebattery, the resistance of the battery contacts and other resistances inthe path between the battery and the electronic components in the phone,which could cause a crash of the software running on the mobiletelephone.

Accordingly, to operate the light source and the transceiversimultaneously additional measures are required. A possible solution isto include ‘super’ capacitors in the transceiver to provide the amountof current required to operate the flash light and the transceiversimultaneously. However, a disadvantage is that capacitors occupy alarge amount of space. Accordingly, the transceiver would be relativelylarge. Furthermore, in case the transceiver is implemented as anintegrated circuit, the capacitors would increase the amount ofsubstrate area required for the circuit. This increases the costs of thecircuit significantly, since the substrate area is a significant factorin the costs of an integrated circuit. Also, the ‘super’ capacitorsintroduce complex mechanical constraints.

SUMMARY OF THE INVENTION

The present invention provides a mobile communications device, acontroller, a method for operating a mobile communication device and akit of parts as described in the accompanying claims.

Specific embodiments of the invention are set forth in the dependentclaims.

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, aspects and embodiments of the invention will bedescribed, by way of example only, with reference to the drawings.

FIG. 1 schematically shows a block diagram of an example of anembodiment of a mobile communications device.

FIG. 2 schematically shows a block diagram of another example of anembodiment of a mobile communications device.

FIG. 3 schematically shows a block diagram of an example of anembodiment of a light source controller.

FIG. 4 schematically illustrates, by way of example, a method ofcapturing an image which may for instance be performed by the example ofFIG. 2.

FIG. 5 schematically shows, by way of example, a timing diagram whichmay, for example, be used by the example of FIG. 1.

FIG. 6 schematically shows a perspective view of an example of a mobilecommunications device in which the examples of FIGS. 1 and 2 may beimplemented.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 and FIG. 2 schematically show block diagrams of examples of amobile communications device 1. The mobile communication device may, asshown in FIG. 1 and FIG. 2, include a communication unit 2 and one ormore other components such as a back light source 14, and/or a display15, and/or a camera 5 and/or a light source 6. The mobile communicationdevice 1 may further include one or more controllers, such as forexample a camera controller 3 and/or a light source controller 4.

As shown in FIGS. 1 and 2, one or more of the controllers 3,4 may beconnected to the communication unit 2 and to one or more of the othercomponents. For instance, in the example of FIG. 2, the light sourcecontroller 4 is connected to the communication unit 2 and respectivelight sources 6, 14. The light source controller 4 can control the lightsources 6,14 during at least a part of a time the communication unit 2is in a communicating mode based on an operation of the communicationunit 2.

The light source controller 4 may for instance be connected to a controloutput 20 of the communication unit 2 to determine a state of thecommunication unit 2 and be connected to respective control inputs60,140 of the one or more other components (e.g. of the light sources6,14) in order to change a state of the component, when thecommunication unit 2 enters into a predetermined state during at least apart of the communicating mode, from a first state to a second state atwhich the component has a lower energy consumption than in the firststate. For example, during the communicating mode, the communicationunit 2 may for instance be in a transmitting state in which thecommunication unit 2 transmits signals to the other device or in anon-transmitting state (e.g. in a receiving state or in a sleepingstate) in which the communication unit 2 does not transmit signals tothe other device. The controller may then control, for example, theother components based on whether the communication unit 2 is in thetransmitting state or a non-transmitting state. For instance, the lightsource controller 4 may switch the light sources 6,14 to a less brightmode.

The mobile communications device 1 may for example include one or morecomponents from the group consisting of: back light, display, camera,light source, microphone, speaker, voice processor communicationprocessor, base-band processor. The components other than thecommunication unit 2 may, for example, be components not required totransmit signals. E.g. such as components providing other functionalitythan voice communication, such as the light source, the camera, the backlight, or the display.

As shown in FIG. 2, the mobile communications device 1 may for exampleinclude a display 15 at which information can be outputted visually. Forexample, data, images, video or other visual information may beoutputted at the display 15 by a processor 8. The mobile communicationsdevice 1 may include a back light 14 which projects light onto a backside from the display 15, in order to illuminate the side of the displayfacing a user and thereby enhance the legibility of the display 15.

As shown in FIGS. 1 and 2, the mobile communications device 1 may forexample include a camera 5 which can capture an image of an object (orof a number of objects). A camera controller 3 may, as shown in FIG. 1,be connected to the camera 5. In the example of FIG. 1, for instance, acamera control output 31 of the camera controller 3 is connected to thecamera 5. The camera controller 3 may control one or more parameters ofthe camera 5, such as the timing of capturing an image by the camera 5,the sensitivity of the camera 5 to light, the zoom of the camera 5, thefocal plane of the camera 5 or other suitable parameters.

In order to enable the camera 5 to capture an amount of light from anobject sufficient to capture the image, the light source 6 canilluminate the object by projecting light on the object. The lightsource controller 4 may be connected to the light source 6. As shown inFIG. 1, for instance, the light source controller 4 may be connectedwith a control input 60 of the light source 6. The light sourcecontroller 4 can control one or more parameters of the light source 6,such as the operating mode of the light source 6, the amount of powerused by the light source 6, the period of time during which light isprojected or any other suitable parameter.

The communication unit 2 may communicate with another device, forexample over a wireless connection. The communication unit 2 may forinstance have a communication mode in which the communication unit 2communicates with another device and a non-communication mode in whichthe communication unit 2 does not communicate.

For example, when switched into the communication mode, thecommunication unit 2 may establish a communication channel over a wiredor wireless connection, e.g. a radio connection. The communication unit2 may for example establish the communication channel according to acommunication protocol, such as define by the Global System for Mobilecommunication (GSM) standard, or a standard in the IEEE 802 series, suchas the 802.11 series. When establishing the communication channel, thecommunication unit 2 may for instance be configured according toinstructions received from another device, such as a base station of amobile telephone network. When switched into the non-communication mode,the communication unit 2 may close the communication channel, and forinstance be reconfigured. The communication channel may for example be abi-directional channel via which the communication unit 2 may transmitand/or receive signals.

The communication unit 2 may for example be in the communicating modeduring a voice call, and be in a non-communicating mode before and afterthe voice call (when, for instance, the mobile communication device 1 isnot used for communication but for example to run software applications,such as a game application or a calendar application). For example, thecommunication unit 2 may alternate in the communicating mode between atransmitting state in which signals are transmitted by the communicationunit 2 and a receiving state in which signals are receiving by thecommunication unit 2. The communication unit 2 may for example allocateda certain period of time to transmit and a certain period of time toreceive signals by a base station or other network controlling device.For example, in a wireless communication networks, such as GSM, a mobilecommunications device typically is assigned a certain period of time toreceive signals and to transmit signals.

In the examples of FIGS. 1 and 2, for instance, the communication unit 2is connected, with a signal output 21, to an antenna 7 and can receiveand/or transmit electromagnetic signals, such as radio signals, over a(not shown) wireless connection to another device, such as a basestation of a mobile telephone network. The communicating mode of thecommunication unit 2 may include a transmitting state in which thecommunication unit 2 transmit signals to the other device and anon-transmitting state in which the communication unit 2 does nottransmit signals (but for example receives signals) to the other device.The light source controller 4 may be arranged to control the lightsource 6 to be in a first state when the communication unit 2 is in thetransmitting state, and control the light source 6 to be in a secondstate when the communication unit 2 is in the non-transmitting state,such that in the first state the light source 6 emits less light than inthe second state.

The light source controller 4 may for example control the light source 6and/or the backlight 14 during at least a part of the communicating modeof the communication unit 2 based on an operation of the communicationunit 2 and on an operation of the camera 5. Thereby, for example, thelight source 6 may be prevented from affecting the communication betweenthe mobile communications device 1 and another device. Also, forexample, the need to provide additional circuitry, such as capacitors,to enable the light source 6 and/or the backlight 14 to use the samepower source as the communication unit 2 may be obviated. For instance,as is explained below in more detail with reference to FIG. 3, the lightsource controller 4 may control the light source 6 to emit lightdepending on the power consumption of the communication unit 2 when thecommunication unit 2 is in the communicating mode. Without whishing tobe bound to any theory, it is found that with such a control, aneffective illumination of the object may be obtained without adverselyaffecting the operation of the communication unit 2. For instance, anexcessive consumption of power from a power source may be prevented bycontrolling the power consumption of the light source 6 such that thepower consumption of the light source 6 is reduced when the powerconsumption of the communication unit 2 increases during thecommunication mode or vice versa.

As shown in FIG. 6, the mobile communications device 1 may include ahousing 13 in which at least a part of the units shown in FIG. 1 (or theunits shown in FIG. 2) may be provided. In the example of FIG. 6, thehousing 13 has a passage in which a part of the camera 5 is placed, morein particular an optical element, such as lens, which can guide lightfrom the object onto light sensitive elements, such as charge coupleddevices. The light source 6 may for example be mounted in the housing13, such that the light generated by the light source 6 is projected inthe viewing direction of the camera 5. In the example of FIG. 6, forinstance, the light source 6 is present in a passage in the housing 13and can project at least a part of the light in a focussing direction ofthe optical element, and hence illuminate objects in the viewing area ofthe camera 5.

The light source controller 4 may be implemented in any suitable manner.The light source controller 4 may, for instance, be connected to thecamera controller 3 and the communication unit 2. In FIG. 1, forinstance, a first controller input 40 is connected to a control output30 of the camera controller 3. A second controller input 41 is connectedto a control output 20 of the communication unit 2. Via the controllerinputs 40,41, the light source controller 4 may receive signals from thecamera controller 3 and the communication unit 2 containing informationabout the operation of the camera 5 and the communication unit 2. Thelight source controller 4 may for example control the amount of currentused by the light source 6 based on the received signals or any otherparameter of the light source 6 suitable for the specificimplementation.

The light source controller 4 may, for example, receive informationabout the mode of the camera 5 and/or the communication unit 3 andcompare the receive information with one or more control criteria. Basedon the comparison, the light source controller 4 may control the lightsource 6. For example, the light source controller 4 may control themode of the light source 6. For example, the light source controller 4may switch the light source 6 from a first mode to a second mode basedon the comparison. The light source controller 4 may for example bearranged to switch the light source 6 from an on-mode to an off-mode, orvice versa, depending on the signals received from the camera controller3. The light source controller 4 may for example switch the light source6 on when the camera 5 capture an image and switch the light source offwhen the camera 5 is not operating.

In the on-mode, the light source 6 may for example be switched betweenstates in which differing intensities of the light emitted by the lightsource 6 depending on the state of the communication unit 2. Thereby,excessive power consumption by the mobile communications device 1 can beprevented effectively, since the communication unit 2 consumes asignificant amount of power during the transmitting state and the powerconsumption of the light source 6 corresponds to the brightness of thelight source 6. The light source controller 4 may for example switch thelight source 6 from an intense mode to a less intense mode, in whichless light is emitted by the light source 6 but the light source isstill emitting light, when the communication unit 2 switches from thereceiving state to the transmitting state (and switch the light source 6from the less intense mode to the intense mode when the communicationunit 2 switches from the transmitting state to the receiving state). Thelight source 6 may for example be in a flash mode when the communicationunit 2 is in the receiving state and be set in a video mode when thecommunication unit 2 is in the transmitting state.

The transmitting state may for example have duration in time which isless than a time required to capture an image with the camera 5. Forexample, the camera 5 may be able to capture between 10 and 50 imagesper second (fps), for example 15 of 30 fps. The communication unit 2 mayalternate between the receiving state and the transmitting state with aperiod of 10 ms or less, such as 4 ms. The communication unit 2 may forexample alternate between the transmitting state and the receivingstate, with a duty cycle of 50% or less and/or above 12.5%. Thecommunication unit 2 may alternate between the receiving state and thetransmitting state in cycles of 10 ms or less, such as 4 ms. During acycle the communication unit 2 may for example be in the transmittingstate for a period in the range from 0.5 milliseconds (ms) to 2 msand/or be in the receiving state for a period in the range from 2 msseconds to 3.5 ms.

The light source 6 may be implemented in any suitable manner. The lightsource 6 may, as shown in FIG. 1 for example, include a light emittingdiode (LED) which is connected with anode contact 60 to the light sourcecontroller 4 and with a cathode contact 61 to ground GND. The lightsource 6 may for example be operated as a flash light or as a continuouslight source. For instance, when the camera 5 is used to capture asingle image, the light source may be operated as a flash light and whenthe camera 5 is used to capture a sequence of images, i.e. a video, thelight source 6 may be operated as a continuous light source. Forexample, the light source 6 may include a LED which uses a current ofabout 200 mA when operated as a continuous light source and in the rangefrom 1 A up to and including about 1.5 A when used as a flash light,with a supply voltage in the range of 0.38 V to 4 V.

FIG. 2 shows another example of a mobile communication device 100. Themobile communication device 100 may, as shown in FIG. 2, include a powersource 10 connected to the communication unit 2 and the light source 6.The power source 10 may for example be a voltage source or a currentsource. The power source 10 may for instance be a DC power source, suchas a battery, a lithium-based chemical battery for example. Thecommunication unit 2 and the light source 6 may for instance use thesame power source 10. The power source 10 may provide power to thecommunication unit 2 and the light source 6. In the example of FIG. 2,the light source 6 is connected to the power source 10 via the lightsource controller 4. More in particular, a current input 60 of the lightsource 6, in this example a light emitting diode, is connected to apower output 43 of the light source controller 4. A current output 61 ofthe light source 6 is connected to ground GND. A current input 44 of thelight source controller 4 is directly connected to the power source 10.

In the example of FIG. 2, the back light 14 is also connected to thepower source 10 via the light source controller 4. More in particular, acurrent input 140 of the back light 14, in this example a light emittingdiode, is connected to a power output 43 of the light source controller4. A current output 141 of the back light 14 is connected to ground GND.

The light source controller 4 may be connected to a power input of thecommunication unit 2 and may be arranged to control the light source 6and/or the backlight 14 based on a consumption of power from the powersource by the communication unit 2. In the example of FIG. 2, forinstance, the communication unit 2 includes a power amplifier 24 and amodem 23. In this respect it should be noted, the term ‘modem’ as usedin this application refers to a device which converts a received signalinto a form suitable for a communication system. The modem may, forexample, convert a received signal into a form suitable to be processedby upper layers of a communication protocol. The modem may, for example,use hardware resources, such as one or more processors and memories toperform demodulation, decoding functions and to process low levelprotocol layers and may execute software.

The modem 23 may, for example, receive signals (to be sent to anotherdevice) from a base-band unit 8 connected with a base-band output 80 toa modem input 230. The base-band unit 8 may for instance present abase-band signal to the modem input 230. The modem 23 may convert thebase-band signal into a signal suitable to be transmitted over theconnection. The modem 23 may for example convert the base-band signalinto a modulated signal with a carrier frequency different from thefrequency of the base-band signal, and present the signal to a signalinput 240 of the power amplifier 24, to transmit the signal to anotherdevice via the antenna 7.

The modem 23 may further control the power provided to the poweramplifier 24, and hence the power consumption thereof. The modem 23 may,as shown in FIG. 2, for example have a power control output 234connected to an on/off contact 244 of the power amplifier 24. Via theon/off contact 244 the power amplifier 24 can be switched on or off byeither providing a high voltage or a low voltage. The modem 23 cancontrol the voltage of the on/off contact 244, and hence switch thepower amplifier 24 on or off. The modem 23 may for example switch thepower amplifier 24 on, and hence into a transmitting state by settingthe voltage to a high voltage and switch the amplifier 24 off by settingthe voltage to a low voltage. In the example of FIG. 2, the light sourcecontroller 4 is connected with a third controller input 42 to the on/offcontact 244. The light source controller 4 can thus sense the voltagesupplied to the on/off contact 244 and hence control the light source 6based on the state of the power amplifier 24. The light sourcecontroller 4 may, as shown in FIG. 3 for example, include power supplycontrol units 45,46 which connect the light source 6 to the power supply10 and control the power supply control units 45,46 based on the voltagesupplied to the power amplifier, as is explained below in more detailwith reference to FIG. 3.

The power amplifier 24 may further have one or more (two in FIG. 2)signal inputs 240,241. At the signal inputs 240,241 one or more signalsto be amplified may be presented. The power amplifier 24 is connectedwith a signal output 242 to the signal output 21, and hence to theantenna. The amplifier 24 can present an amplifier signal to the antenna7, in order to transmit the signal to another device via a wirelessconnection. The signal inputs 240,241 may, as shown in FIG. 2, beconnected to signal outputs 231, 232 of the modem 23 and the modem 23may generate and present the signals to be amplified to the signalinput(s) 240,241.

The power amplifier 24 may, as shown in FIG. 2, be connected with apower supply contact 243 to the power supply 10. Between the powersupply 10 and the power amplifier 24 a voltage converter 25 may bepresent. In the example of FIG. 2, for instance, a voltage converter 25is connected with a low voltage contact 251 to the power source 10 andwith a high voltage contact 250 to the power amplifier 24. The voltageconverter 25 can convert the voltage provided by the power source 10 toa higher voltage, for example from a voltage below 5 V, such as 3.7 V,to a voltage above 10 V, such as 12 V or 15 V. In the example of FIG. 2,a converter control contact 252 of the converter 25 is connected to aconverter control output 233 of the modem. Via the converter controlcontact 252, for example, the voltage conversion ratio may becontrolled.

The light source controller 4 may include a first controller input 40connected to the camera controller 3. In the example of FIG. 2, thefirst controller input and the second controller input 41 are connectedto a processor 8. The processor 8 is connected with a supply 85 to thepower source 10. The processor 8 is connected with an input/output 80 tothe communication unit, to receive or transmit signals from and to thecommunication unit. The processor 8 is further connected with a firstlight source control output 81 to the first controller input 40 of thelight source controller 4. A second light source control output 82 ofthe processor 8 is connected to the second controller input 41 of thelight source controller 4. At the first light source control output 81,the processor 8 can output a signal which controls the mode of the lightsource, e.g. on or off. For example, when the camera 5 captures animage, the mode may be controlled to be the on-mode whereas the mode maybe set to be the off-mode when the camera 5 does not capture an image.At the second light source control input 82, a signal can be presentedwhich controls the state of the light source, e.g. high level of lightor low level of light. For example, when the camera is used as a videocamera, the level of light may be controlled by the processor 8 to below, and in case the camera is used as a photo camera, the level oflight may be controlled to be high.

In the example of FIG. 2, a camera control output 83 of the processor isconnected to the control input 30 of the camera controller 3. Theprocessor 8 may for example transmit to the camera controller 3 a startsignal in response to which the camera controller 3 starts generation ofan image and/or receive from the camera controller 3 data representingone or more images and output the images, for example at a (not shown)user interface in a for humans perceptible form. When the start signalis being sent, or slightly prior thereto, the processor 8 may e.g. setlight source 6 in the on-mode via the first light source control output81.

In the example of FIG. 2, a communications input/output 84 of theprocessor 8 is connected to an input/output 90 of a voice communicationprocessor 9. The voice communication processor 9 is connected to amicrophone 11 and to a speaker 12, via respective signal inputs/outputs91,92. The voice communication processor 9 can control the microphone 11and the speaker 12 and process signals received from the microphone orto be outputted at the speaker 12.

Referring to FIG. 3, the light source controller 4 may be connected withthe first controller input 40 to the first light source control output81. Via the first controller input 40, the mode of the light source canbe controlled, e.g. on or off, as shown in table 1. As shown in FIG. 3,the light source controller may include a comparator unit. Thecomparator unit may compare the signal at the second controller inputand the signal at the third controller input with a light source controlcriterion, which comparator unit may be further connected to thecontroller output, for controlling the light source based on a result ofthe comparison.

In the example of FIG. 3, for example, the comparator includes a logicexclusive AND (XAND) gate 48. The XAND gate 48 is connected with aninput to the second controller input 41 and with an inverted input tothe third controller input 42. The XAND gate 48 is connected with anoutput to a control input of a switch 47. The switch 47 connects a powersupply port 44, which can be connected to the power source 10, to aselected one of power supply control units 45,46. The power supplycontrol units 45,46 are connected to the power output 43. The powersupply control units 45,46 each provide a different amount of power tothe power output 43, and hence to the light source. The state of theswitch 47 is controlled by the signal presented at the switch controlinput, and hence by the output of the XAND gate 48. Depending on thestate of the switch 47, the power supply control unit 45 or the otherpower supply unit 46 is connected to the power supply and hence either afirst current or a second current is supplied to the light source 6.Table 1 is a truth table which lists the state and mode of the lightsources 6 and the state of the backlight 14 as a function of the signalpresented at the inputs 40-42.

TABLE 1 input 40 input 41 input 42 light source 6 light source 6 backlight 14 1 1 1 ON low high 1 1 0 ON low low 1 0 1 ON low high 1 0 0 ONhigh low 0 1 1 OFF — high 0 0 1 OFF — high 0 1 0 OFF — low 0 0 0 OFF —low

The controller 4 may include a comparator 49 for sensing comparing aparameter forming a measure for an amount of energy available from thepower source 10 with a predetermined control criterion and controllingthe state of the component based on the comparison. In the example ofFIG. 3, for instance, the input 44 forms a sensing contact and isconnected to an input of a comparator 49. The comparator 49 can comparethe voltage at the input with a threshold voltage TR at reference input.The comparator 49 may for example output a logical true signal (e.g.a 1) in case the voltage at the input is higher than the thresholdvoltage and output a logical false signal (e.g. a 0) in case the voltageat the first input is lower than the threshold voltage. As shown in FIG.3, the comparator 49 may for example be connected to the input 42, andhence control the switch as explained above. Thereby, in case the supplyvoltage of the power source 10, which may for example be a battery,becomes below the threshold voltage, the light source 6,14 may beswitched to a lower consumption mode. Since the supply voltage forms ameasure for the energy in a battery, and typically reduces when thebattery is almost empty, the lifetime of the power source can beextended.

The camera 5 may be any suitable type of camera. In the example of FIG.1, for instance, the camera is a digital camera. The digital camera may,as shown, include a matrix-like sensor which includes a plurality of asensor elements 51-5 i arranged in rows and columns, such as chargecoupled device sensors, complementary metal-oxide semiconductor (CMOS)sensors or another suitable type of photo-sensor. As shown in FIG. 1,the camera 5 may include a lens 51 or other optical element whichprojects light onto the matrix of sensor elements 51-5 i. Forillustrative purposes, in FIG. 1 a line-shape arrangement of fivesensors is shown and in FIG. 2 a two-dimensional matrix arrangement offive-by-five sensors is shown. However the matrix arrangement mayinclude any suitable number of n by m sensors, with m equal or differentto n. The matrix may for example be an array of more than 500 pixels bymore than 400 pixels, 640 by 480 pixels or 2048 by 1536 pixels. Thearrangement may for example be rectangular and for example have alength:width ratio of 1.25 or more, such as 1.33 or more, for example1.77 or more.

The camera controller 3 may be implemented in any suitable manner. Thecamera controller 3 may for example be arranged to send the capturedimage to another device. In the example of FIG. 1, for instance, thecamera controller 3 is connected with an image output 33 to an imageinput 22 of the communication unit 2. The camera controller 3 can senddata representing the captured image to the communication unit 2, viathe image output 33 and the image input 22. The communication unit 2 maysubsequently transmit the data to another device, for example via theantenna 7 and a wireless connection to the other device. However, theimage may also be captured for different purposes, and for example bestored in a (not shown) memory in the mobile communications device 1 orbe outputted on a (not shown) display.

The light source controller 4 may for example control the light sourceto be in the on-mode during a period of time longer than inverse of thenumber of images the camera can capture per seconds, for example abouttwo times or more than two times that period. Thereby, the light sourceis controlled in a manner which may be used to project light on anobject of which camera without mechanical shutter, such as a so-calledrolling-shutter camera, captures an image. In table 2, examples ofvalues for the duration of the flash light are listed as a function ofthe number of frames the camera may capture.

TABLE 2 Camera speed equal or larger than: Time of flash equal or largerthan: (frames per second) (ms) 7.5 272 10 205 15 138 20 105 25 85 30 72

FIG. 4 schematically illustrates generation of an image with arolling-shutter camera. A rolling-shutter camera may include a matrixarrangement of photo-sensitive sensor elements 51-5 i, as e.g. shown inFIGS. 1 and 2. When capturing an image, a sub-image is captured per lineof the matrix and the sub-images are combined thereafter into thecomplete image. More in particular, a line-shaped subgroup ofphoto-sensitive cells is activated, the light is projected onto thecells 51-5 i in the respective line during an exposure period. Followingthe exposure time, the sensor elements are read out and the sensorelements are reset to provide a defined exposure time. Using adata-processing unit, for example the camera controller 3, which hassuitable means of processing such as, for instance, means of digitizing,storing, calculation, etc., an image can be produced from the readlines. As is illustrated in FIG. 4, the camera may capture an image Fnwhich may be part of a sequence of images . . . , Fn−1, Fn, Fn+1, . . .or be a single separate image. As illustrated, when capturing the imageFn, the line of sensor elements denoted 511-5 i 1 is first activated,exposed and readout. Thereafter, the process is repeated with afollowing line 512-5 i 2, etc., until the last line of elements denoted51 j-5 ij in FIG. 2 is activated, exposed and readout. In the example ofFIG. 4, the lines are read after each other in the period of timedenoted T2, but the processes for the lines have an overlap in time. Thelast line is activated a period of time T1 after activation of the firstline.

FIG. 5 schematically illustrates the current Ibat provided by the powersource 10, the current Ifls used by the light source 6 and the currentItrx used by the communication unit 2 in the communicating mode. Forillustrative purposes, the graphs have not been drawn to scale to helpimprove the understanding of the embodiments of the present invention.As shown, the communication unit 2 may switched in the communicatingmode between a transmitting state in which a high amount of current, forexample more than 0.5 mA, such as 1.5 mA, or more, is used by thecommunication unit 2 and a receiving state in which a low amount ofcurrent is used by the communication unit 2 for example less than 0.4 mAsuch as 0.3 mA. The switching between the transmitting state and thereceiving state may for example have a period which is less than thetime required to capture an image, for example less than 5 ms, such as4.6 ms. The switching may for example which is less than the timerequired to activate, expose, read and reset a line of a sensor elements51 j-5 ij. The ratio of the switching period relative to time requiredto activate, expose, read and reset a line may for example be in therange of 1:20 to 1:5. The light source 6 is switched to an on-mode whenthe camera 5 starts capturing the image Fn, and switched to off-modewhen the last line of elements denoted 51 j-5 ij has been read out. Inthe on-mode, the light source 6 is switched between the high state andthe low state when the communication unit 2 is switched between thetransmitting state and the receiving state. Accordingly, as shown inFIG. 4, the current provided by the power source 10 remains relativelylow.

The invention may be implemented as a kit. The kit may be provided as aset of separate components which can be connected to each other toassemble a module operating as controller 4, or may be provided as anassembled module of components connected to each other in a suitablemanner.

The invention may also be implemented in a computer program for runningon a computer system, at least including code portions for performingsteps of a method according to the invention when run on a programmableapparatus, such as a computer system or enabling a programmableapparatus to perform functions of a device or system according to theinvention. Such a computer program may be provided on a data carrier,such as a CD-ROM or diskette, stored with data loadable in a memory of acomputer system, the data representing the computer program. The datacarrier may further be a data connection, such as a telephone cable or awireless connection.

In the foregoing specification, the invention has been described withreference to specific examples of embodiments of the invention. It will,however, be evident that various modifications and changes may be madetherein without departing from the broader spirit and scope of theinvention as set forth in the appended claims. For example, othercomponents, such as the speaker 12 or the voice communication processor9, may be controlled based on the operation of the communication unit 2and for example be switched on or off depending on the state of thecommunication unit 2.

For example, it should be understood that all circuitry described hereinmay be implemented as one or more integrated circuits, for exampleimplemented in silicon or another semiconductor material oralternatively be implemented as a software code representation of one ormore integrated circuits or parts thereof.

Also, the invention is not limited to physical devices or unitsimplemented in non-programmable hardware but can also be applied inprogrammable devices or units able to perform the desired devicefunctions by operating in accordance with suitable program code.Furthermore, the devices may be physically distributed over a number ofapparatuses, while functionally operating as a single device. Forexample, the light source controller 10 and/or the communication unit 2may be implemented as suitably connected discrete semiconductorcomponents.

Also, devices functionally forming separate devices may be integrated ina single physical device. For example, the base-band unit 8, the lightsource controller 4, and the voice communication processor 9 may beintegrated into a single processor.

Furthermore, the mobile communications device may, for example, be amobile telephone, a personal digital assistant, a camera provide with awireless communication unit to enable transmission of captured images orvideo to, e.g., a person computer or another type of mobilecommunication device.

However, other modifications, variations and alternatives are alsopossible. The specifications and drawings are, accordingly, to beregarded in an illustrative rather than in a restrictive sense. In theclaims, any reference signs placed between parentheses shall not beconstrued as limiting the claim. The word ‘comprising’ does not excludethe presence of other elements or steps then those listed in a claim.Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to‘only one’, but instead are used to mean ‘one or more’, and do notexclude a plurality. The mere fact that certain measures are recited inmutually different claims does not indicate that a combination of thesemeasures cannot be used to advantage.

1. A mobile communications device, comprising: a communication unit forcommunicating with another device; a camera for capturing an image of anobject; a camera controller for controlling said camera; and a lightsource for illuminating said object in order to enable the camera tocapture an amount of light sufficient to capture the image; a lightsource controller having a controller output connected to said lightsource, for controlling said light source, wherein the light sourcecontroller is connected to said communication unit and said cameracontroller, for controlling, when said camera is capturing an image ofan object and said communication unit is in said communicating mode,said light source to emit light having an intensity which is sufficientto provide an effective illumination of the object and which depends onthe power consumption of the communication unit; and wherein said lightsource controller is connected to an control output of saidcommunication unit, for determining a state of said communication unitand to a control input of said light source for changing a state of saidlight source from a first state to a second state at which said lightsource has a lower energy consumption than in said first state when saidcommunication unit enters into a predetermined state during at least apart of said communicating mode.
 2. A mobile communications device asclaimed in claim 1, wherein, during said communicating mode acommunication channel is established between the communication unit andsaid other device, and in said communicating mode, the communicationunit can be in a transmitting state in which said communication unittransmits signals to said other device over said communication channelor in a non-transmitting state in which the communication unit does nottransmit signals to said other device over said communication channel.3. A mobile communications device as claimed in claim 1, wherein saidlight source controller includes: a comparator connectable to a powersource, for comparing a parameter forming a measure for an amount ofenergy available from the power source with a predetermined controlcriterion and controlling the state of the light source based on thecomparison.
 4. A mobile communications device as claimed in claim 2,wherein said light source controller is arranged to control said lightsource to be in a first state when said communication unit is in thetransmitting state, and control said light source to be in a secondstate when said communication unit is in the non-transmitting state, inwhich first state said light source emits less light than in said secondstate.
 5. A mobile communication device as claimed in claim 4, whereinwhen said communication unit is in said communicating mode, thecommunication unit alternates between said transmitting state and saidnon-transmitting state, and said transmitting state has a duration lessthan a time required to capture an image with said camera.
 6. A mobilecommunications device as claimed in claim 4, wherein said light sourcecontroller is arranged to switch said light source between a video modeand a flash light mode.
 7. A mobile communication device as claimed inclaim 4, including a connect for a power source, for providing power tosaid communication and wherein said light source controller is connectedto a power input of said communication unit and is arranged to controlsaid light source based on a consumption of power from said power sourceby said communication unit.
 8. A mobile communication device as claimedin claim 7, wherein said light source controller is arranged to controlsaid light source to be in said second state when said communicationunit uses a first amount of power and said second state when saidcommunication unit uses a second amount of power, said second amount ofpower being higher than said first amount of power.
 9. A mobilecommunications device as claimed in claim 5, wherein said communicationunit alternates with cycles of 10 ms or less and said camera is able tocapture between 10 and 50 images per second.
 10. A mobile communicationsdevice as claimed in claim 1, wherein said light source controller isarranged to control said light source in a first mode when said cameracaptures an image of said object and to control said light source to bein a second mode when said camera does not capture an image.
 11. Amobile communication device as claimed in claim 1, wherein in said firstmode said light source can be in a first state or in a second state, inwhich first state and second state said light source emits light butless light in the first state than in said second state.
 12. A mobilecommunications device as claimed in claim 10, wherein said first mode isa light emitting mode and said second mode is an off-mode.
 13. A mobilecommunications device as claimed in claim 11, wherein during saidcommunicating mode a communication channel is established between thecommunication unit and said other device, and in said communicating modethe communication unit can be in a transmitting state in which saidcommunication unit transmits signals to said other device over saidcommunication channel or in a non-transmitting state in which thecommunication unit does not transmit signals to said other device oversaid communication channel; and wherein said light source controller isarranged to control said light source to be in the first state when saidcommunication unit is in the transmitting state, and control said lightsource to be in the second state when said communication unit is in thenon-transmitting state.
 14. A mobile communications device as claimed inclaim 1, wherein said light source controller includes: a firstcontroller input connected to said camera controller; a secondcontroller input connected to said communication unit; and a comparatorunit connected to said first controller input and said second controllerinput, for comparing at least one signal received at said firstcontroller input and at least one signal received at said secondcontroller input with at least one light source control criterion, whichcomparator unit is further connected to said controller output, forcontrolling said light source based on a result of said comparison. 15.A mobile communication device as claimed in claim 1, wherein said camerais rolling shutter camera.
 16. A mobile communications device as claimedin claim 1, wherein, during said communicating mode, the communicationunit can be in a transmitting state in which said communication unittransmits signals to said other device or in a non-transmitting state inwhich the communication unit does not transmit signals to said otherdevice.
 17. A mobile communications device as claimed in claim 1,wherein said light source controller includes: a comparator connectableto a power source, for comparing a parameter forming a measure for anamount of energy available from the power source with a predeterminedcontrol criterion and controlling the state of the light source based onthe comparison.
 18. A light source controller for a mobilecommunications device comprising a communication unit for communicatingwith another device in a communicating mode; a camera for capturing animage of an object; a camera controller for controlling said camera, anda light source for illuminating an object in order to enable said camerato capture an amount of light sufficient to capture the image, saidlight source controller comprising: a controller output connectable to alight source a communication unit for communicating with another devicein a communicating mode; the light source controller being connectableto said communication unit and said camera controller, for controllingan emission of light be said light source during at least a part of timesaid communication unit is in a communicating mode, based on anoperation of said communication unit and on an operation of said camera,wherein said light source controller is arranged to control, when saidcamera is capturing an image of an object and said communication unit isin said communicating mode, said light source to emit light having anintensity which is sufficient to provide an effective illumination ofthe object and which depends on the power consumption of thecommunication unit, and wherein said light source controller isconnected to an control output of said communication unit, fordetermining a state of said communication unit and to a control input ofsaid light source for changing a state of said light source from a firststate to a second state at which said light source has a lower energyconsumption than in said first state when said communication unit entersinto a predetermined state during at least a part of said communicatingmode.
 19. A method for controlling a mobile communications device,including: communicating by a communication unit in the mobilecommunication device with another device; capturing an image of anobject with a camera in the mobile communications device whileilluminating said object by a light source with an amount of lightsufficient to capture the image; controlling said light source, whensaid camera is capturing an image of an object and said communicationunit is in said communicating mode, to emit light having an intensitywhich is sufficient to provide an effective illumination of the objectand which depends on the power consumption of the communication unit;determining a state of said communication unit; changing a state of saidlight source from a first state to a second state at which said lightsource has a lower energy consumption than in said first state when saidcommunication unit enters into a predetermined state during at least apart of said communicating mode.